Many vehicles generally have a prime mover or internal combustion engine, a transmission to transmit drive power to move the vehicle, and a mechanism to selectively transfer rotational torque from the prime mover to the transmission. In some approaches, the mechanism to selectively transfer rotation from the prime mover to the transmission includes a manual clutch. A manual clutch is efficient. However, operation of the manual clutch requires extra effort and added operational oversight by the vehicle operator. Such extra effort and added operational oversight can be less desirable, for example as it can reduce the operator's efficiency. An alternative mechanism to transfer rotational torque from the prime mover to the transmission is a torque converter.
A torque converter is generally a hydrodynamic fluid coupling that typically transfers the rotational torque from a prime mover to a driven load such as a transmission. The torque converter multiplies the torque from the prime mover and transfers the torque to the transmission. United States patent application number 2011/0124456 to Sung discloses a launching device, transmission device and a torque combining device. The launching device, the transmission device, and the torque combining device are disposed on a first power delivery shaft directly connected to the engine. The launching device, the transmission device, and the torque combining device are disposed in a sequence of the launching device, the transmission device, and the torque combining device from the engine. The torque converter of the launching device includes a front cover connected to a crankshaft of the engine, an impeller connected to and rotating with the front cover, a turbine facing the impeller, and a stator disposed between the impeller and the turbine and delivering automatic transmission oil flowing out from the turbine to the impeller after changing flowing direction of the automatic transmission oil.
However, torque converters are typically less efficient, result in poor fuel economy, have hydraulic losses and the like in comparison to a mechanical clutch. Additionally, a torque converter in larger vehicle applications requires a great deal of torque transfer that can exasperate these problems. Moreover, due to the increased torque requirements of larger vehicles, a larger sized torque converter is typically required and this increases the cost of production and increases space requirements.
Accordingly, a torque converter that is more efficient, improves fuel economy, and reduces hydraulic losses is needed. Additionally, a torque converter having a reduced size and reduced cost of production is also desirable.